JP6534251B2 - Incineration method of solid industrial waste - Google Patents

Description

  The present invention relates to an incineration method for solid industrial waste, and more particularly to an incineration method for reducing the erosion of refractory materials in incinerators.

  In the industrial waste incineration facility, the inner wall of the incinerator is lined with a refractory to protect the furnace wall from high temperature harmful gases. The refractories are subject to damage as the furnace is used and require regular replacement.

As a factor to damage the refractory material,
(1) Damage caused by heat, where the refractory material itself melts by operating under the heat resistance temperature of the refractory material or the refractory material receives a heat shock due to a rapid change in temperature conditions (2) rotary furnace etc. When it is used on the inner wall surface of the material, mechanical damage may occur due to cyclical application of mechanical stress, or the refractory material may be scraped off due to abrasion with the contacting material, mechanical damage (3) melting of the material When the material intrudes into the interior of the refractory material, it causes a change in the composition of the refractory material, resulting in loss of heat resistance and strength, and chemical damage.

  Conventionally, in order to protect the refractory material against these factors and to prevent damage, measures have been taken to lower the combustion temperature or use a high-grade refractory material that is relatively resistant to damage. Alternatively, a common refractory was used and replaced each time it was damaged.

  However, when the combustion temperature is kept low, not only the processing speed is lowered, but also the odor removal of the combustion gas becomes difficult, and the cost for safely performing the gas processing becomes high. Also, the use of high-grade refractory materials that are not easily damaged has limited service life and is expensive. Furthermore, when using a general refractory material, it must be replaced frequently every time it is damaged, which is not only expensive and time-consuming, but also causes problems such as interruption of waste incineration during replacement.

  On the other hand, Patent Document 1 discloses a method of covering the surface of a porous refractory material with a glass film with a glass lining.

JP, 2002-174419, A

  However, the method of Patent Document 1 also requires the cost of the coating material and the labor of coating operation, and further, there is a problem that the waste incineration treatment is interrupted during the coating operation.

  An object of the present invention is to suppress damage to a refractory material easily and at low cost and without interrupting the incineration of waste when incinerating solid industrial waste.

In order to solve the above problems, the present invention relates to a method of incinerating solid industrial waste, comprising 1% by mass or more and 2% by mass or less of slaked lime or equivalent calcium to the waste before incineration treatment. The present invention provides a method for incinerating solid industrial waste characterized in that melting of incineration ash is prevented by adding the calcium-containing substance to be contained and performing incineration treatment after mixing.

Of ash after incineration, CaO (wt%) / mean value of the basicity represented by SiO ₂ (mass%) is preferably 0.40 to 2.0. The content of silicon oxide in the industrial waste may be 10% by mass or more.

  According to the present invention, damage to refractories can be suppressed by a simple method and at low cost without interrupting waste incineration treatment.

It is the schematic which shows the structure of the waste disposal facility concerning the Example of this invention.

  Hereinafter, embodiments of the present invention will be described.

  In the past, refractory materials lined in a rotary kiln, which is an incinerator that performs waste incineration treatment, usually needs to be repaired in 7 to 8 months due to damage. The present inventors mainly have a low melting point of incineration ash because the basicity of waste incineration ash is as low as about 0.3 on average, and the incineration ash is melted, whereby the refractory material has a structure I thought that it was to cause spalling.

  Then, it has been found that if the calcium-containing substance is added to the solid waste to be incinerated and the melting point is raised by raising the basicity of the incineration ash, the inside of the refractory material is less likely to be corroded. Therefore, when burning wastes using an incinerator lined with a refractory material, the present invention is a calcium-containing material containing 1 mass% or more of slaked lime or equivalent calcium to waste before incineration. It was decided to add.

If the calcium-containing substance is added to the waste to raise the basicity, the melting point of the incineration ash will rise, and the incineration ash will be difficult to melt. Thereby, the penetration to the refractory material of incineration ash molten material is suppressed, and structural spalling of a refractory material becomes difficult to occur. That is, damage to the refractory can be suppressed and the life can be extended. In order to obtain a sufficient effect, it is preferable to make the basicity of incineration ash into 0.4 or more on average. The basicity is the ratio of mass% of CaO to SiO ₂ in incinerated ash (CaO (mass%) / SiO ₂ (mass%)). However, it is desirable to suppress the basicity to 2.0 or less. When the basicity exceeds 2.0, the melting energy unit increases remarkably due to the increase of the melting temperature, and when the temperature in the furnace rises more than expected and the incineration ash is melted, the fluidity becomes extremely high, and it is due to permeation It is because damage of a refractory material will become large.

  The basicity (average 0.4 or more) of incinerated ash is made by so-called trend management. There are a large number of incineration ash, the components are not necessarily the same, and the basicity of the incineration ash itself changes largely to about 0.2-1. In addition, since the treatment is carried out continuously in large quantities daily, it is not productive to constantly monitor the components of the incineration ash. Therefore, the amount should be about once a day, so measure the basicity of the incineration ash, set the alkali amount to adjust the basicity of the incineration ash, and add the amount to the solid waste of each treatment scheduled for the day Do. In addition, as a sampling method of the incineration ash, for example, once every four hours, a total of six samplings per day are carried out, and a total of six samples per day are mixed and then fractionated after the mixing. Can be a representative sample of Even in this case, the basicity is not always 0.4 or more on this day, but by repeating this operation every day, the basicity tends to be 0.4 or more in the long run It becomes the implementation of management and can suppress the wear and tear of refractory materials.

  The calcium-containing substance may be calcium hydroxide, calcium carbonate, gypsum, or any other powder or mud-like substance containing calcium. Moreover, what mixed 2 or more types of these may be used. These calcium-containing substances are preferably in the form of particles, solutions, or slurries from the viewpoint of preventing melting by uniformly mixing them in the waste. For example, in the case of calcium carbonate, the average particle diameter is preferably 50 μm or less.

  Such calcium-containing substances are introduced into solid industrial waste to be incinerated and uniformly stirred, and then the waste is incinerated in an incinerator, whereby the basicity of generated incineration ash is increased, and the incineration ash is incinerated. The melting point of Therefore, it becomes difficult to fuse | melt (erode) inside a refractory material, and it leads to prolongation of a refractory material.

  The invention is particularly effective when the silicon oxide content of the waste is 10% by weight. Furthermore, it is effective when the heat-resistant temperature of the refractory material lined in the incinerator is 1000 ° C. or higher.

  Thus, the present invention can suppress damage to a refractory material by a very simple method of adding a calcium-containing substance when incinerating solid industrial waste. As a result, the life of the refractory can be extended, the replacement cycle can be extended, and costs and labor can be reduced. In addition, since the refractory material is not subjected to an operation such as coating the surface with a protective material, there is no need to interrupt the incineration treatment by the operation. Therefore, it is possible to reduce the odor of combustion gas and the chance of the generation of dioxin caused by the temperature decrease accompanying the shutdown of the incinerator.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such examples. It is apparent that those skilled in the art can conceive of various changes or modifications within the scope of the technical idea described in the claims, and the technical scope of the present invention is also natural for them. It is understood to belong to

  Changes in thickness of refractory material when implementing the incineration method of the present invention incineration after adding a calcium-containing substance to waste and the conventional incineration method incinerating without adding a calcium-containing substance and The basicity of incinerated ash was measured.

  FIG. 1 is an outline of the configuration of the waste treatment facility 1, and arrows in the figure indicate the flow of waste. The waste is transported by the shovel car 2 and introduced into the skip conveyor 3 and then introduced into the rotary kiln 6 which is an incinerator via the apron conveyor 4 and the slide gate 5. The rotary kiln 6 had a diameter of 4.9 m and a length of 14 m.

Refractory material (Al ₂ O ₃₎ : An incinerator is used without adding a calcium-containing substance to waste for about 6 months from January 15, 2007 to July 10, 2007 The thickness of 89%, SiO ₂ : 4%, Cr ₂ O ₃ : 5%) was measured. In addition, the thickness measurement of the refractory material was implemented by making a 80- to 100-mm diameter cylindrical hole in the refractory material and measuring the thickness of the hole portion. In the incineration treatment, 6 to 10 t / h of the waste was put into the rotary kiln 6, and the rotary kiln 6 was incinerated at 900 to 1100 ° C. for about 1 hour. The thickness measurement results of the refractory material are as shown in Table 1, and the thickness reduction rate was 24.9 mm / month on average.

Further, fluorescent X-ray analysis was performed once a week, and the CaO and SiO ₂ concentrations were calculated by converting them from the obtained Ca and Si concentrations, and the basicity of the incinerated ash was determined. The fluorescent X-ray analysis was performed using a fluorescent X-ray analyzer "OURSTEX 160" manufactured by ARSTEC Corporation, and calibration with a standard substance was performed in advance before this measurement. The basicity of the incinerated ash remained in the range of 0.20 to 0.49, and the average for about 6 months was 0.33.

Next, for about 6.5 months of October 19, 2012 to May 1, 2012, as the embodiment of the present invention, after slaked lime is put into waste, it is incinerated in an incinerator and the inner lining of the incinerator The thickness of the refractory material (Al ₂ O ₃ : 83%, SiO ₂ : 6%, Cr ₂ O ₃ : 10%) was measured.

  First, after preparing solid waste 144 to 200 t to be incinerated in a pit, 2 mass% of slaked lime was added to the waste. The waste in the pit was scooped with an automatic shovel, and stirred with a shovel for about 1 hour so that slaked lime in the waste became uniform. The waste was adjusted to pH 7 to 11 using a moisture content of 28.4 to 64.7% on a wet basis.

  The waste material to which slaked lime was added was transported to the waste treatment facility 1 by the shovel car 2 and was introduced to the rotary kiln 6 at 6 to 10 t / h via the skip conveyor 3, the apron conveyor 4 and the slide gate 5 shown in FIG. . And in the rotary kiln 6, incineration processing was performed at 900-1100 degreeC for about 1 hour.

  The thickness measurement results of the refractory material are as shown in Table 2, and the thickness reduction rate was 11.3 mm / month on average.

  In addition, fluorescent X-ray analysis was performed once a day to determine the basicity of incinerated ash. The basicity of incinerated ash remained in the range of 0.27 to 0.72, and the average for about 6.5 months was 0.48.

  By applying the present invention, the average value of basicity is increased, and the thickness reduction rate of the refractory material is significantly reduced. That is, the life of the refractory material is longer than before, and the repair or replacement cycle can be extended more than twice.

  The present invention can be applied as a method for reducing the deterioration of refractory materials of waste incinerators.

1 Waste Disposal Equipment 2 Excavator 3 Skip Conveyor 4 Apron Conveyor 5 Slide Gate 6 Rotary Kiln

Claims (3)

In the method of incinerating solid industrial waste,
Before incineration treatment, calcium-containing material containing 1% by mass or more and 2% by mass or less of calcium hydroxide or calcium content with respect to the waste is added, mixed and incinerated to melt the incineration ash A method of incinerating solid industrial waste characterized in that The average value of the basicity represented by CaO (mass%) / SiO ₂ (mass%) of the incinerated ash after incineration treatment is characterized by being 0.40 or more and 2.0 or less. The incineration processing method of the solid industrial waste as described. The method for incinerating solid industrial waste according to claim 1 or 2, wherein the silicon oxide content of the industrial waste is 10% by mass or more.

Images